EP1159193A1

EP1159193A1 - Device for airport ground lighting system

Info

Publication number: EP1159193A1
Application number: EP00907753A
Authority: EP
Inventors: Pierre Maillard; Michel Legrand; Paul Nicolas
Original assignee: ECT Industries; Ulmer Aeronautique
Current assignee: ECT Industries; Ulmer Aeronautique
Priority date: 1999-03-05
Filing date: 2000-03-02
Publication date: 2001-12-05
Also published as: AU2923100A; WO2000053494A1; FR2790443A1; FR2790443B1

Abstract

The invention concerns an airport lighting system embedded in the ground and comprising light sources with light emitting diodes arranged at several levels which associated with a combination of mechanical and optical means enables to provide above-average illumination in outstanding conditions of reliability. The invention is applicable to all types of airport ground lighting systems.

Description

LUMINOUS FLOOR MARKING DEVICE FOR AIRPORT

The present invention relates to a lighting device included in the ground which can be applied in particular to the marking of runways and airport runways and which has many advantages compared to previous devices.

Currently, airport ground beacons, which must be carried out in a standardized limited volume, use one or more light sources combining high-power incandescent lamps, reflectors and prisms, placed in a reinforced housing, to emit standardized light fluxes in one or more directions.

These devices have the disadvantage of requiring frequent preventive replacement of the lamps to avoid breakdowns which would be a danger for aircraft.

Furthermore, said lamps do not easily provide illumination strictly in accordance with the required standards without precise positioning of their filaments, positioning difficult to ensure without a tool for measuring illumination. The aging of said lamps does not itself guarantee a standard-compliant illumination for a long period of time.

In addition, the quality of illumination is progressively reduced by pollution of all kinds which deposit on the exterior surface of the prisms, starting with its lower part. This last point makes compliance with standards very difficult to maintain.

Finally, the efficiency of the lamps is low and this therefore constitutes a source of significant energy expenditure. By the use of light-emitting diodes judiciously chosen and arranged to produce the light sources, the present invention provides a solution to the problems mentioned above, and which relate to energy saving, service life, reliability, lighting efficiency and compliance with lighting standards over time.

Indeed, by combining the use of light-emitting diodes having various radiation patterns and by means of periodic cleaning of the prisms, it is possible to best meet the standards of illumination of all kinds of beacons for periods which may exceed 80,000 hours .

The lifetime of said light-emitting diodes is itself greater than 100,000 hours, which greatly reduces the risk of failure.

The diodes can be arranged so that the light mainly comes out through the upper part of the beacon optics, which has the effect of delaying the reduction in efficiency by fouling, and this by strictly respecting the standards of height of said beacons relative at the slopes.

A technique of superimposing the diodes in several levels, so that the bodies of the diodes of the upper levels constitute an optical element for the light coming from the diodes of the lower levels, makes it possible to very significantly increase the illumination obtained without increasing the outlet surface which is always limited by the space available.

The invention therefore relates to a ground lighting beacon for an airport of the type comprising:

- a housing emerging from the ground over a reduced part of its height,

- at least one light source and preferably two, - At least one optical output device and preferably two, characterized in that the light source is produced by an assembly of light-emitting diodes.

Embodiments of the invention will be described below, by way of nonlimiting examples, with reference to the appended drawings in which:

FIG. 1 is a presentation of the typical distributions of the light intensity which must be provided by an airport beacon,

FIG. 2 is a block diagram, in vertical section, of a beacon according to the invention,

FIG. 3 is a block diagram in top view of the tag of FIG. 3,

FIG. 4 is a presentation of the various possible arrangements of light-emitting diodes in a first variant of the tag of FIGS. 2 and 3,

FIG. 5 is a presentation in three views of an arrangement of light-emitting diodes in a preferred variant of the tag of FIGS. 2 and 3, and

FIG. 6 is a presentation in two views of a variant of the light source of the beacon in FIGS. 2 and 3.

FIG. 7 is a presentation of a wide field variant of the light source of the beacon of FIGS. 2 and 3.

Figure 1 shows five illumination diagrams to be provided in one direction by the various airport beacons. These diagrams are each characterized by two domains angular, one at high power where the illumination must have a minimum value I and a minimum average value Im, the other at lower power where only a minimum value I is specified. Each of these domains is defined by an angle η in a horizontal field and by an angle τσ in a vertical field.

The five areas are characterized as follows.

Figure la:

Im> 20 cd for -10 ° <η <10 ° and + 1 ° <m ≤ 8 °

I> 10 cd for -10 ° <η <10 ° and + 1 ° <w ≤ 8 °

I> 2 cd for -lβ ° <η <16 ° and + 0 ° <τσ <13 °

Figure lb:

Im> 200 cd for -3.5 ° <η <3.5 ° and + 1 ° <m ≤ 8 °

I> 100 cd for -3.5 ° <η <3.5 ° and + 1 ° <τπ ≤ 8 °

I> 20 cd for -4.5 ° <η <4.5 ° and + 0 ° <m ≤ 13 °

Figure the:

Im> 100 cd for -19.25 ° <η <19.25 ° and + 1 ° <w ≤ 10 °

I> 50 cd for -19.25 ° <η <19.25 ° and + 1 ° <τσ <10 °

I> 10 cd for -21.25 ° <η <21.25 ° and 0 ° <τπ ≤ 15 °

Figure ld:

Im> 20 cd for -10 ° <η ≤ 10 ° and + 1 ° <TÏÏ ≤ 4 °

I> 10 cd for -10 ° <η <10 ° and + 1 ° <r_ ≤ 4 °

I> 2 cd for -16 ° <η <16 ° and + 0.5 ° <tπ <10 °

Figure the:

Im> 20 cd for -19.25 ° <η <19.25 ° and + 1 ° <τσ <4 °

I> 10 cd for -19.25 ° <η ≤ 19.25 ° and + 1 ° <TO <°

I> 2 cd for -20.50 ° <η <20.50 ° and 0.5 ° <m ≤ 10 ° If we consider the diagram in figure le which presents the illumination diagram requiring the maximum overall power, we see that the field covered represents approximately 0.1 steradian. The minimum flux to be supplied is therefore 5 lumens. For a conventional filament lamp, this flux corresponds to a light power of approximately 5.10 ^"2 Watts. Given the impossibility of obtaining uniform illumination throughout the field with a conventional lamp, the light power to be actually supplied is very superior to guarantee the minimum illumination at the edge of the field The light output of the filament lamps being very low, it was therefore advisable to use high-power lamps in the beacons of the prior art.

As shown in FIGS. 2 and 3, the tag according to the invention notably comprises:

a housing 1, produced in two parts, a lower part 2 and an upper part 3, - at least one, and preferably two light sources, 4 and 5 having an emission axis 34 and 35 respectively,

- at least one and preferably two prisms, 6 and 7,

- one or more supply circuits 8 and 9.

The upper part 3 of the housing 1, of generally substantially circular shape and with a vertical axis, comprises:

a substantially planar outer ring 10 having an upper surface 17,

a central bulge 11 having an upper surface 12 also substantially planar, of elongated shape, bordered by two large rectilinear sides,

at least one and preferably two openings 13 and 14, located on either side of the central bulge 11,

- A central lower recess 15, placed under the central bulge 11, and such that it leaves under the surface 12 a sufficient thickness to guarantee the mechanical strength of the assembly under a heavy load, - near the periphery, a substantially circular lower recess 16,

To comply with the standards in force, the central bulge 11 is located approximately 12 mm above the upper surface 17 of the outer crown.

The openings 13 and 14 are intended to receive the light sources 4 and 5 as well as the prisms 6 and 7. They are preferably inclined symmetrically towards the outside and have two parts:

- an outer part, respectively 18 and 19, of relatively elongated general rectangular shape, the major axis of which is horizontal, and the corners of which are preferably rounded, the rounding being able to be such that the ends of said openings are semi-circular, - an inner part, respectively 20 and 21, also of generally rectangular shape, but of smaller dimensions than those of the outer parts 18 and 19, so that a counterbore, respectively 22 and 23, constitutes the junction between said two parts 18 and 20 on the one hand, 19 and 21 on the other hand, and forms a sort of open bottom for the external parts 18 and 19.

Each of these two openings opens onto the outside on each side of the bulge 11, one of the long sides of their outer parts 18 and 19 forming a stop, respectively 24 and 25, with one of the long sides of said bulge 17, the two other long sides of said outer parts 18 and 19 forming a stop, respectively 26 and 27, with the upper face 17 of the outer ring 10. The prisms 6 and 7 have an entry face, respectively 28 and 29, and an exit face, respectively 30 and 31, which form between them an angle α whose imaginary edges 32 are substantially parallel to the edges 24 and 25 of the upper part 3 of the housing 1.

These prisms 6 and 7 are mounted in prism holders 36 and 37 respectively, by means of a flexible material 33 so that their entry face is substantially perpendicular to the axis of the corresponding light source, respectively 34 and 35.

The prism holders 36 and 37 have dimensions such that they are housed in the external parts, respectively 18 and 19 of the openings 13 and 14, and come to bear on the countersinks 22 and 23 of said openings. They carry, on their periphery, near their bearing face on the counterbores 22 and 23, a groove 38 in which is placed a seal 39.

They are fixed to the upper part 3 of the housing 1 by screws 40 and are removable from the outside. They can therefore be replaced to be cleaned or repaired without it being necessary to remove the beacon from its location.

Sources 4 and 5 are introduced into the interior parts, respectively 20 and 21, of the openings 13 and 14 and fixed by means adapted to the upper part 3 of the housing 1.

The inclination α of the openings 13 and 14 relative to the horizontal plane therefore determines the inclination of the axes 34 and 35 of the sources 4 and 5. This inclination results from an optimization between: - the angle β of the prism formed by the two input and output faces of said prism, - the refractive index of the glass constituting said prism,

- the inclination of the light beam at output δ,

- The standard protrusion of the bulge 11 relative to the surface of the ground and the minimum thickness of said bulge to ensure its mechanical strength.

To obtain the normalized inclination δ of the light beam at the output of 5.5 degrees, the inclination α of the openings 13 and 14, relative to the horizontal, is between 30 and 40 degrees for an angle β of the prism between 25 and 40 degrees and for a refractive index of glass between 1.4 and 1.85.

In the preferred embodiment of the invention, the inclination α of the openings 13 and 14 relative to the horizontal is substantially equal to 35 degrees with an angle β of the prisms substantially equal to 28 degrees and an index of the glass constituting the neighboring prism of 1.8.

The light sources 4 and 5 are constituted by an assembly of light-emitting diodes 41 which can be of any shape. In the preferred embodiment of

1 invention, the selected diodes comprise a body 42 substantially cylindrical or elliptical with axis 43, terminated at one of its ends by a surface 44 substantially hemispherical or ellipsoidal and at the other by a substantially planar surface 45. The light is emitted by a radiating source 66 placed substantially from said hemispherical or ellipsoidal surface 44 from which it exits in a cone 45 whose shape depends on the construction characteristics of the diode and whose axis 47 is substantially parallel to axis 43 of the body 42 of said diode. The electrical supply is made by connections 48 which exit from the flat face 45.

The light-emitting diodes 41 can be placed in numerous arrangements on one or more levels. FIG. 4 shows the possible arrangements on a level, arrangements generally usable when the light power to be supplied for the beacon is not too large compared to the power of the light-emitting diodes available. These arrangements may include, for example, a single row of at least two diodes, Figure 4a, two parallel rows, side by side, Figure 4b, or nested, Figure 4c. The number of diodes and the number of rows, placed side by side or nested, can be adapted so as to fill the available space as best as possible, without departing from the scope of the invention. The light emitting diodes can be mounted so that they are tangent to each other by generatrices of the cylinders which constitute them. They can also be kept apart to promote cooling.

When the available location is too small to obtain the necessary illumination, and in a preferred embodiment of the invention, as shown in FIG. 5, the light-emitting diodes 41 are arranged on two levels, an upper level 49 and a lower level 50 so that the light emitted by the diodes of the lower level passes through a space 76 where the diodes of the upper level are located.

The upper level 49 comprises at least one row 77, having an axis 78, and preferably two or more rows, of at least two diodes 41, placed in parallel, two adjacent diodes being separated by a pitch 79, at least equal to their width and preferably less than twice their width, the rows 77 being separated by a center distance 80. The lower level 50 preferably comprises the same number of rows of diodes 81 as the upper level, of at least one diode each and placed below the diodes 41 of the upper level, their axes 78 being substantially superimposed, so that the diodes 81 of the lower level are offset substantially by one half pitch 79, along the axis 78, with respect to the diodes 41 of the upper level and thus their apex 51 is opposite a zone 52 where two diodes 41 of the upper level are close or tangent, this arrangement allows to pass the connections 48 of the upper level diodes on each side of a zone 53 where the lower level diodes are close or tangent.

The diodes of the upper level 49 can be chosen with an output beam 56 forming a wide angle γ and it is advantageous to use diodes whose output beam is elliptical and to orient them so that the greatest width of the beam is substantially parallel to the largest dimension of the field to be covered. The diodes of the lower level 50 are advantageously chosen with a narrower output beam 54.

The rays of the beams 54 emitted by the diodes of the lower level 50, enter the diodes of the upper level 49 through their planar part 45 while undergoing a refraction which tends to slightly tighten said beams. These then pass through the diodes of said upper level passing by the radiating sources 66 of said diodes and emerge through their hemispherical or ellipsoidal part 44 while undergoing a new refraction, much greater than the previous one. This last refraction tends to widely spread the rays and to create exit beams 55 having an angle φ analogous to the angle γ of the exit beams 56 of the diodes of the upper level 49. The body 42 and the hemispherical or ellipsoidal end 44 diodes of the upper level thus constitute an additional optical element for shaping the light emitted by the diodes of the lower level. This arrangement can obviously be applied with any number of rows and any number of diodes on each of the two levels.

In the preferred embodiment of the invention, the upper level comprises two rows of 15 diodes having a beam elliptical output covering 70 degrees in width and 30 degrees in height, while the lower level has two rows of 14 diodes having a circular beam covering 15 degrees.

In a variant of the preferred embodiment of the invention, as shown in FIG. 6, the diodes 41 are also arranged on at least two levels. The upper level 49 also has at least two rows 77 of at least two diodes 41 placed in parallel, FIG. 6a, two adjacent diodes 41 being separated by a pitch 79 at least equal to their width and preferably less than twice their width , the rows 77 being separated by a center distance 80. The lower level 50 comprises at least one row 82 of at least one diode 64, offset by a half pitch 79 along the axis 78 and by a half inter-axis 80 perpendicular to said axis, so that said diode 64 emits most of its light in a space 65 delimited by four quarter circles and left free between four diodes 30, 31, 32 and 33 for example, adjacent two two in two rows 77 of the upper level 49. This arrangement can be applied with any number of rows of any number of diodes at the upper level. Figure 6b shows the application with three rows on the upper level and two on the lower level. It is obvious that it is possible to place at the lower level a number of rows of light-emitting diodes equal or greater than that of the upper level, as shown in FIG. 6c for example and without departing from the scope of the invention.

All the diodes of each of the sources are placed in a dust-tight enclosure consisting of a transparent window 78, a wall of substantially rectangular shape 82 and a printed circuit 60 on which said diodes are fixed and welded. These printed circuits 60 provide the electrical connections and the supply of said diodes. They also make it possible to position and fix the corresponding sources 4 and 5 in the upper part 3 of the housing 1 so that they are placed as high as possible in the internal parts 20 and 21 of the openings 13 and 14, so that the light which they emit mainly comes out by the upper part of the diodes and thus the tag retains its quality despite the fouling of the lower part of the prisms located closest to the upper surface 17 of the crown 10.

In a variant of the invention, the printed circuit of one or two sources can be broken down into two or more planes, three for example, 61, 62 and 63, inclined with respect to each other, as shown by the FIG. 7, so as to orient the light-emitting diodes of said source in at least two different directions and thus to provide illumination over an angle λ wider than the angles γ or φ obtained with a plane printed circuit 60.

The use of a curved molded printed circuit, in the form of a portion of a cylinder, a portion of a sphere or of any other shape, makes it possible to obtain very varied light distributions and therefore to respond easily. to any kind of lighting specification.

Finally, the lower part 2 of the housing 1 is formed by a cylinder 67, of substantially vertical axis, the upper end 68 of which is open and the lower end of which is closed by a bottom 69. The upper end 68 is surrounded by a ring 70, substantially horizontal.

The bottom 69 is arranged to receive a connector 71 for connection and, for this purpose, includes a bulge 72 adapted to said connector. The crown 70 has on its upper part a circular groove 73 in which a gasket 74 is placed. This lower part 2 is fixed by the crown 70 in the circular recess 16 of the upper part 3 of the housing 1 using screws 75.

Claims

1. Airport light beacon device of the type comprising: - a box (1) emerging from the ground over a reduced part of its height,

- at least one light source and preferably two (4 and 5), constituted by light-emitting diodes (41),

- at least one optical output device and preferably two (6 and 7), characterized in that the light-emitting diodes (41) constituting each light source are distributed over at least two levels, an upper level (49) and a level lower (50), so that the light emitted by the diodes of said lower level passes through a space (76) of the upper level occupied by the diodes placed on said level.

2. Device for lighting the ground for an airport according to claim 1, characterized in that each level of diodes comprises at least one row (77), having an axis (78), of light-emitting diodes and preferably several rows placed side by side. dimension and having between them a center distance (80), each row of the upper level having at least two diodes (41) and preferably several placed substantially side by side and aligned with a pitch (79) at least equal to the width d '' a diode and preferably less than twice this width, each row of the lower level having at least one diode (81) and preferably several also placed substantially side by side and aligned with a pitch substantially equal to the pitch (79) of the diodes

(41) of the upper level, at least one row of the lower level being placed under a row of the upper level, with an offset along the axis (77) substantially equal to half a step (80), at least a row of the lower level being placed under a row of the upper level, their axes (78) thus being substantially superimposed, with an offset the along said axes (78) substantially equal to half a step (79) so that a beam (54) of light emitted by a diode in this row of the lower level passes through an area (52) where two diodes of the level upper are close and preferably tangent, a part of said light entering at least one of said diodes, by a planar face (45) forming one of the two ends of said diode, and emerging from the other end (44).

3. airport ground lighting device according to claim 1, characterized in that each level of diodes comprises at least one row of light-emitting diodes and preferably several rows placed side by side and having between them an axis (78 ), each row (77) of the upper level (49) having at least two diodes (41) placed substantially side by side and aligned with a pitch (79) at least equal to the width of a diode and preferably less than two times this width, each row (82) of the lower level (50) having at least one diode (64) and preferably several also placed substantially side by side and aligned with a pitch substantially equal to the pitch of the diodes of the upper level, at least a row of the lower level being offset by a half pitch (79) parallel to the axis (78) by a row (77) and by a half distance between axes (80) perpendicular to said axis so that the largest part of the lu light emitted by the diodes (64) of the row (82) of the lower level (50) passes into spaces (65) delimited by four diodes of the upper level (49), adjacent to each other in pairs (56, 57, 58 and 59).

4. Airport light beacon device according to claim 1, characterized in that each source emits in a main direction of emission (34 and 35) making with the horizontal plane an angle between 30 and 40 degrees and preferably close to 35 degrees, in that the light emitted by each source is reoriented by a prism making an angle β having a substantially horizontal fictitious edge, in that this angle β is between 25 and 40 degrees and preferably substantially equal to 28 degrees and in that this prism consists of a glass having a refractive index between 1.4 and 1.85 and preferably close to 1.8, this in order to obtain an inclination of the light beam close to 5.5 degrees.

5. Device for lighting the ground for an airport according to one of claims 1, 2 or 3, characterized in that the light-emitting diodes constituting each light source are enclosed in a sealed enclosure.

6. Airport light beacon device according to one of the preceding claims, characterized in that each source is offset upwards relative to the entry face of the corresponding prism so that the light emitted mainly comes out through the upper part of said prism.

7. Device for lighting the ground for an airport according to one of claims 1, 2 or 3, characterized in that the light-emitting diodes of the same source are oriented in at least two different directions so as to obtain an angle of more extensive lighting.

8. Device for lighting the ground for an airport according to claim 1, characterized in that it emits a light intensity defined in two angular domains, one at high power where the illumination must have a minimum value I and a value minimum average Im, the other at lower power where the illumination at another minimum value I, each of these domains being defined by an angle η in a horizontal field and by an angle τπ in a vertical field, the values Im and I being defined by:

Im> 20 cd for- -10 ° <η ≤ 10 ° and + 1 ° <τπ ≤ 8 ° I> 10 cd for -10 ° <η ≤ 10 ° and + 1 ° <τσ <8 ° I> 2 cd for -16 ° <η ≤ 16 ° and + 0 ° <τπ ≤ 13 °

9. Airport ground lighting device according to claims 1 and 10, characterized in that the values Im and I are defined by: Im> 200 cd for -3.5 ° <η <3.5 ° and + 1 ° <τπ ≤ 8 ° I> 100 cd for -3.5 ° <η ≤ 3.5 ° and + 1 ° <τπ ≤ 8 ° I> 20 cd for -4.5 ° <η <4.5 ° and + 0 ° <τπ <13 °

10. Airport ground lighting device according to claims 1 and 8, characterized in that the values Im and I are defined by: Im> 100 cd for -19.25 ° <η ≤ 19.25 ° and + 1 ° <tσ < 10 ° I> 50 cd for -19.25 ° <η <19.25 ° and + 1 ° <τπ ≤ 10 ° I> 10 cd for -21.25 ° <η <21.25 ° and + 0 ° <τπ ≤ 15 °

11. Ground lighting device for airports according to claims 1 and 8, characterized in that the values Im and I are defined by: Im> 20 cd for -10 ° <η ≤ 10 ° and + 1 ° <τπ ≤ 4 °

I> 10 cd for -10 ° <η <10 ° and + 1 ° <τπ ≤ 4 °

I> 2 cd for -16 ° <η <16 ° and + 0.5 ° <τπ ≤ 10 °

12. Ground lighting device for airports according to claims 1 and 8, characterized in that the values Im and I are defined by:

Im> 20 cd for -19.25 ° <η ≤ 19.25 ° and + 1 ° <τπ ≤ 4 ° I> 10 cd for -19.25 ° <η ≤ 19.25 ° and + 1 ° <τπ ≤ X

I> 2 cd for -21.25 ° <η ≤ 21.25 ° and 0.5 ° <τπ <10 °